JSON Commands Cheat Sheet

JSON
Cheat

JavaScript Basics

Examples


{
  "name": "Jason",
  "age": 39,
  "height": 1.92,
  "gender": "M",
  "salary": 70000,
  "married": true,
  "children": [
    {"name": "Tom", "age": 9, "gender":"M"},
    {"name": "Ava", "age": 7, "gender":"F"}
  ]
}

Types

Number

Double precision floating-point

String

Series of characters

Boolean

true or false

Array

Ordered sequence of values

Value

String, Number, Boolean, null etc

Object

Unordered collection of key/value pairs

null

Null or Empty

Objects


{
  "color": "Purple",
  "id": "210",
  "composition": {
    "R": 70,
    "G": 39,
    "B": 89
  },
  "empty_object": {}
}

Multiple key/value pairs separated by a comma

2D Array


{
  "my_sequences": [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9, 0],
    [10, 11]
  ]
}

Nested


{
  "Jack": {
    "id": 1,
    "name": "Franc",
    "salary": 25000,
    "hobby": ["a", "b"],
    "location": {
        "country": "A", "city": "A-A"
    }
  }
}

String

Double quote

Backslash

Forward slash

Backspace

Form feed

Newline

Carriage return

Tab

Trailed by four hex digits

Number

Integer

Digits 1-9, 0 and positive or negative

Fraction

Fractions like 0.3, 3.9

Exponent

Exponent like e, e+, e-, E, E+, E

Arrays


[1, 2, 3, 4, 5]

Begins with [ and ends with ]

Array of objects


 {
  "children": [
    {"name": "Jimmy Smith", "age": 15},
    {"name": "Sammy Sosa", "age": 12}
  ]
}

Object of arrays


{
  "attributes": ["a1", "a2"],
  "methods": ["getter", "setter"],
  "empty_array": []
}

Object of objects


{
  "Mark McGwire": {
    "hr": 65,
    "avg": 0.278
  },
  "Sammy Sosa": {
    "hr": 63,
    "avg": 0.288
  }
}

Access JSON in JavaScript

Access Objects


let myObject = {
  "name": "Jason",
  "last": "Doe",
  "age": 39,
  "gender": "M",
  "salary": 70000,
  "married": true
};

myObject.name

"Jason"

myObject["name"]

"Jason"

myObject.age

myObject.other

undefined

myObject.[0]

undefined

Access Array of Objects


let myArray = [
  {
    "name": "Jason",
    "last": "Doe",
    "age": 39,
    "gender": "M",
    "salary": 70000,
    "married": true
  },
  {
    "name": "Tom",
    "last": "Smith",
    "age": 42,
    "gender": "F",
    "salary": 80000,
    "married": true
  },
  {
    "name": "Amy",
    "last": "Burnquist",
    "age": 29,
    "gender": "F",
    "salary": 60000,
    "married": false
  }
];

myArray[0]

{"name": "Jason", ...}

myArray[1].name

"Tom"

myArray[1][2]

myArray[3]

undefined

myArray[3].gender

TypeError: Cannot read...

Access Array


let myArray = [
  "Jason",
  "Doe",
  39,
  "M",
  70000,
  true
];

myArray[1]

"Doe"

myArray[5]

true

myArray[6]

undefined

Access Nested


let myObject = {
  "ref": {
    "name": 0,
    "last": 1,
    "age": 2,
    "gender": 3,
    "salary": 4,
    "married": 5
  },
  "jdoe": [
    "Jason",
    "Doe",
    39,
    "M",
    70000,
    true
  ],
  "jsmith": [
    "Tom",
    "Smith",
    42,
    "F",
    80000,
    true
  ]
};

myObject.ref.age

myObject["ref"]["age"]

myObject.jdoe

["Jason", "Doe", 39 ...]

myObject.jsmith[3]

"F"

myObject[1]

undefined

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What is a JSON Cheat Sheet?

A JSON commands cheat sheet would typically contain information related to parsing, manipulating, and creating JSON data. JSON, or JavaScript Object Notation, is a data interchange format. However, remember that JSON itself doesn’t have "commands." It’s a data format, similar to XML, and it doesn’t have operations or functions. Instead, you use your programming language to work with JSON data.

What is JSON

JSON stands for JavaScript Object Notation. It is a lightweight data-interchange format that is easy for humans to read and write and easy for machines to parse and generate.

JSON is a text format that is entirely language-independent but uses conventions familiar to programmers of the C family of languages, including C, C++, C#, Java, JavaScript, Perl, Python, and many others. These properties make JSON an ideal data-interchange language.
JSON is a format for structuring data and is often used to pass data from a server to a web page or application. The JSON format involves pairs of keys and values. Keys are always strings, while values may be strings, numbers, booleans, objects, arrays, or null.

Here's an example of what JSON data might look like:

{ "name": "John", "age": 30, "city": "New York" }

Learn JSON in 10 Minutes

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